The present application is directed to a climatic test chamber and a refrigeration system that is adapted to cool the test chamber.
Climatic test chambers are used to test products that are exposed to a range of climatic conditions in order to determine how the products will perform in such conditions. Such test chambers may require a refrigeration system that is capable of achieving a wide range of temperature and humidity conditions such as from positive 180 degrees Centigrade to minus 73 degrees Centigrade in the test space. To achieve such low temperatures, it is known to use cascade refrigeration systems having high stage and low temperature stage linked by an intermediate cascade heat exchanger. The cascade heat exchanger acts as the evaporator on the high stage system and the condenser on the low stage system allowing the low stage to operate at much lower temperatures. Such cascade refrigeration systems may also be operable in single stage mode in which the high stage system has one or more additional climate control evaporator(s) that are capable of supplying high stage temperature cooling and/or humidity control to the test chamber. The low stage compressor is off during single stage mode.